Phenolic compounds are highly bioactive compounds which are widely present in plants (fruits and vegetables) and natural beverages (tea, coffee, wine etc.). Biological effects associated with phenolic compounds include antioxidant, anti-carcinogenic, anti-inflammatory and antibacterial activities which contribute to various health benefits. Although phenols are mainly natural compounds, there are also phenolic compounds, with high antioxidant activity, obtained by synthetic pathways, both natural and synthetic phenols being used in food and beverage, pharmaceutical and cosmetic industries.
The aim of the present study is to assess by comparison the antioxidant activities of natural and synthetic phenolic compounds. Therefore, one natural phenolic compound (caffeic acid) and two synthetic phenols (butylated hydroxyanisole and propyl gallate) are evaluated by 2,2-diphenyl-1-picryhydrazyl (DPPH∙) assay and consist of determination of antioxidant compounds capacity to scavenge the synthetic free radical, DPPH∙, and calculating the reaction rates between phenolic compounds and DPPH∙. For each compound, ethanolic solutions of 1 mM, 0.2 mM, 0.1 mM, 0.05 mM are prepared, and their antiradical activities are determined in the presence of 1mM ethanol solution of DPPH∙ by UV-VIS spectrophotometry. Propyl gallate showed the highest antiradical activity up to thirty seconds. The highest DPPH· reaction rate of 2.4 µM/s was obtained for caffeic acid solution at 1mM for the time range up to one minute of reaction.